This project aims at defining the role of glucagon in normal and disordered states of carbohydrate metabolism in the fetus, newborn and child. Sensitive radioimmunoassays for pancreatic glucagon and for glucagon like immunoreactivity will compliment existing techniques for the measurements of insulin growth hormone, glucose and fatty acids. These techniques will be employed to: a) Determine the maturation and interrelationship of glucagon secretion in the fetal sheep, employing the chronically catherized pregnant sheep preparation. b) Compare and contrast the control of glucagon and insulin secretion in Vitro from perfused pancreas and pancreatic islets obtained from animals of varying ages. c) Determine the extent of glucagon secretion in normal infants and children, and in those with hypo and hyperglycemia syndromes. d) Examine the contribution of glucagon to the pathogenesis and maintenance of diabetes mellitus in humans and in genetically predisposed animal models.